The present invention relates generally to generator cooling, and more particularly, to an apparatus and method to stabilize a fan for cooling an engine driven generator.
Engine driven welding machines or welders generate considerable heat and noise during operation, which are undesired characteristics of the device. One source of heat generation in a welder is a generator which combines with other components to increase the temperature of the operating environment. Another undesirable byproduct of welder use is noise generation which occurs primarily due to the operation of a fan that cools the generator and an external engine that drives the generator. In a proper operating environment, the welder must have sufficient heat removed to keep the engine, generator, and other components at suitable operating temperatures. A failure to maintain the proper operating environment will result in the output of the welder becoming limited due to the rise in temperature, which is undesired.
Historically, noise emanates from the generator due to the rotation of the fan which operates to cool the generator. Prior art machines utilized different fans to produce airflows through the generator. Such fans were generally connected to a rotary shaft having a hub member at one end of the rotary shaft with a plurality of fan blades connected thereto. The fans were generally complete, unitary pieces with each of the fan blades and hub constructed from a metal, such as aluminum. Constructing the fan blades of a unitary metal material stabilized the fan during rotation and reduced vibrational noise. Some such prior art devices further include fins positioned on the fan blades that were spaced apart from one another and extend outwardly from the fan blades.
The prior cooling and noise reduction efforts for engine driven welding machine generators are not completely satisfactory. Constructing fan blades of metal materials such as aluminum and steel can be costly. Moreover, it is desirable to reduce noise generated by a welder to provide safer and user-friendlier operating conditions. Furthermore, excess noise due to vibration of the fan blades is also a concern. Rotation of the fan can result in increased noise levels at certain harmonic frequencies, which are a function of the size, shape, and materials that form the fan.
There is a need for an apparatus capable of reducing noise vibrations of a rotary fan during cooling of an engine driven welding machine generator in a more efficient manner than current fan configurations. It would therefore be desirable to have a more economical fan blade arrangement capable of preventing harmonic frequency vibrations from occurring in a fan.
The present invention is directed to a system and method to cool an engine driven welding machine generator more economically and with reduced noise vibrations by stabilizing the fan blades about an annular lip of a hub rotated by a rotary shaft to overcome the aforementioned concerns.
The present invention includes a fan fixed to one end of a rotary shaft. Upon transmission of a driving force to the rotary shaft by a flywheel, the fan rotates to cool a generator, such as a generator of an engine driven welding machine. The fan is constructed of at least one fan blade segment that extends away from the rotating shaft and have a plurality of fins on the fan segments. Nearest protrusions are generally separated by respective arc distances such that at least two of the arc distances of the fan are unequal. A flex plate is also included to secure the fan blades to a hub.
In accordance with an aspect of the present invention, a fan is disclosed and includes a fan blade assembly having an inner arcuate end. The fan further includes a hub having an inner annular lip and an outer annular lip, the outer annular lip adapted to receive the inner arcuate end of the fan blade assembly. The fan also has a flexible plate having an aperture therethrough to receive the inner annular lip therein, the plate attached to the hub and fan blade assembly and configured to provide flexation to the fan blade assembly.
In accordance with another aspect of the present invention, a system for cooling an engine driven welding machine generator includes a rotary shaft having a first end rotatably attached to a generator housing. The rotary shaft is rotated by transmission of a driving force applied thereto by a flywheel through a flex plate. The system has a hub fastened to a second end of the rotary shaft and at least two fan blade segments configured to engage an outer annular lip of the hub. The flex plate is affixed to the flywheel and has at least two fan blade segments mounted thereto. The plate also has an aperture to receive an inner annular protrusion of the hub therein.
In accordance with the process of the present invention, a method to stabilize a fan for cooling an engine driven welding machine generator has two steps. One step includes positioning a number of fins to at least one fan segment such that adjacent fins have unequal spacing therebetween. The other step includes connecting the at least one fan segment between a hub and a plate.
Various other features, objects and advantages of the present invention will be made apparent from the following detailed description and the drawings.